DE1671334A1 - Method and device for the continuous coking of solid fuels by means of fine-grain heat carriers - Google Patents

Description

METALLGESELLSCHAFT Frankfurt (MainJ, Z6 J Jaguar 1967

Aktiengesellschaft DrWer / GM

Patent Department
Professor No. 5170

Method and device for continuous coking of solid fuels by means of fine-grained heat

carrier. .... ......

The production of metallurgical coke has so far been done by high-temperature coking Baking coal in dormant shifts in batch operation in (indirectly) externally heated chambers. This discontinuous way of working requires a low specific output and high construction costs.

The proven one for smoldering (low-temperature coking or degassing) direct heating with hot flushing gases is essential for the production of high-temperature coke only applicable in exceptional cases, because between deirpeissen Purge gas and the coke at temperatures above 700 C gasification reactions can occur that attack the coke structure and reduce the coke strength.

This reduction in coke strength during continuous coking which - otherwise, through lower system costs and high specific performance excels, can be avoided if instead of the flushing gas a

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fine-grained solid heat transfer medium, ζ. B. sand or fine coke is used. As a result of the better heat transfer from the fine-grained heat transfer medium to the coking material can be compared to the known flushing gas process achieve a further increase in / specific performance.

The smoldering of lumpy coal in the presence of sand or fine-grained coal Coke was exported decades ago. However, these known methods still worked with external heating. The addition of fine-grain, solids had the purpose to improve the heat transfer to the coal charge and / or the mechanical stresses of the resulting Lump coke to decrease during the passage through the Ofan. In this connection, a method has been developed in which Briquettes smoldered in a mixture with non-baking, fine-grain coal The fine-grained coke is used to embed the compacts and is later used to produce the briquettes.

Bekanni are still processes for smoldering or coking lumpy pieces Fuels, according to which highly heated sand acts as a heat carrier with the fuels brought into contact, separated again after heat transfer has taken place is heated again and returned to the coking system in the circuit. It both rotary tubes and shaft furnace are described / which after this Working principle are operated.

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For several years, work has been going on in many places, the irregularly shaped To replace mining coke with molded coke. One goal of these aspirations is to provide the coal base for the production of metallurgical coke broaden, so that non-baking fuels or those with a low baking capacity, which is not sufficient for the usual retort coking, can be used for the production of high-temperature coke. A Another goal is the blast furnaces, which recently more and more with Ore pellets are charged, including the coke as a uniformly shaped ^ P

It is important to add a more even gas flow through the shaft filling and to achieve better operating results of the blast furnaces.

Briquetting and are particularly suitable for shaping the coke the Peller tier on. In both cases you can both at outside temperatures work as well as at elevated temperatures, at which that before the molding added binder is soft. The type of design and the one involved

selected temperature are based essentially on the ¹ JB used

Raw materials. Elevated temperatures between e.g. 380 and 520 ° C are preferably used when briquetting or pelletizing, if fine-grained to dusty charcoal is used as a binder, the

is in the plastic state at these "temperatures. ♦ ^:

The composition of the briquettes, briquettes or pellets can be very different be different. It depends on the properties of the insert ^ '

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fabrics. The suitable mixtures range from moist charcoal with binding. Additions of less than 0.5% over coal-y coke mixtures differing Ratio with or without additional binder up to the fine coke / foreign binder mixture. In the case of moldings from coal-coke mixtures, the coke component both of foreign origin and also of the coal to be briquetted. In the latter case, this coke is after current state of the art in a separate apparatus, for example in a fluidized bed, produced from fine-grained coal. Also for moldings The fine coke component is usually made from coke and foreign binders this way.

The invention is directed to a process for continuous coking solid fuels in a shaft furnace with heat supply through circulating, fine-grained heat transfer medium and a shaft furnace for carrying out the process. It is based on the task of broadening the coking coal base and providing metallurgical molded coke to the existing technology simplify, improve the heat management and the construction costs of the plants. It has been found that there is an improvement in the process and a simplification of the apparatus if the Production of the fine coke takes place in the same apparatus in which the coking of the bricks is carried out, and if one uses the fine coke produced inside this apparatus as a heat transfer medium in the circuit leads from the one Partial flow is branched off for the production of the moldings. According to the invention ^

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is a known process for degassing fine-grain fuels by means of hot coke as a heat carrier with the coking of lumpy fuels in a shaft furnace in Jer way that both for the Coking of the fine coal as well as the briquettes the same, self-made, Fine coke, which is circulated, serves as a heat carrier and is brought into direct contact with the coking material.

The invention relates to a process for the production of molded coke from fine-grain fuels, which are deformed by briquetting or pelletizing in a shaft furnace by direct heating with fine-grain Coke as a heat carrier that flows in parallel with the moldings through / shaft furnace wi rd ..

The inventive method is characterized in that fine-grained Coal and the briquettes are coked in the same process that the fine coke formed from the fine coal is used as a heat carrier and in the Circuit is passed through the shaft furnace and a heating zone, and that branched off a partial flow of the fine coke from the heat transfer circuit and used as a component for the production of the briquettes will.

Non-baked fine coal and the bricks can be coked together in the shaft furnace.

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Baking hard coal is expediently first coked by mixing it with the hot heat transfer medium, and the resulting hot mixed coke is then brought to act on the briquettes. The moldings can be dried or smoldering and or gently using hot purge gases before mixing with the heat carrier.

The hot exhaust gas from the heating of the heat transfer medium can be used as the flushing gas or the degassing gas of the coking after reheating by direct heat exchange with the hot forming coke can be used.

Depending on the type and the baking capacity of the fine coal used and on the behavior of the moldings during coking, there are various embodiments of the method according to the invention. A very simple coking technique allows briquettes, which are produced on roller presses from a hot mixture of hot fine coke and finely ground baking charcoal that has been preheated to the plastic state. These briquettes do not require drying or preheating, since they are hot and can be exposed to shock-like heating immediately by mixing with highly heated fine coke.

If the fine coke, which is used in the process according to the invention as a heat carrier and serves as a component of the mixture to be briquetted or pelleted.

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made from non-baking charcoal, then the briquettes and the fine charcoal leisurely in contact with the hot heat transfer medium in the shaft furnace to be brought. -

If the fine coke is made from fine coal with a greater or lesser baking capacity made, then it is advantageous to start with this for yourself with the hot To mix the heat transfer medium and to coke and only the dab.ei arising Bring mixed coke with the moldings in contact. This pre-degassing Baking fine coal can be done in such a way that fine coal and briquettes are introduced into the shaft furnace at different heights. The pre-degassing but can also be connected in a special one connected to the shaft furnace Zone, from which the mixed coke is then used as a hot heat transfer medium the shaft furnace is introduced. As the direct heating of the briquettes by Contact with the Aieissen heat transfer medium in the event of a very high level of heat penetration suddenly occurs, the associated rapid degassing would damage the structure of the Blow up briquettes or pellets or at least loosen them, which would lead to a low strength of the molded coke produced.

Cold formed briquettes or pellets that are e.g. moist and / or a lot Containing bitumen or volatile components are expedient of the Dried together with the hot heat transfer medium by means of a flushing gas and heated and, if necessary, also pre-degassed, i.e. smoldered. These Pretreatment can also be useful for some hot pellets if these have a lot of volatile components.

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The drying and / or degassing of such bituminous and / or or moist briquettes are expediently carried out in one of the shaft furnaces upstream treatment room or several such. As already described above, the exhaust gas from the heating medium can be used as the flushing gas or re-heated coking gas can be used.

Three examples may serve to explain the invention in more detail: each of which is accompanied by a flow chart.

In the embodiment according to FIG. 1, heibriquettes are enforced and the heat transfer medium is produced from non-baking fine coal.

In the embodiment according to FIG. 2, hot briquettes are used and the heat transfer medium is made from non-baking hard coal.

In the embodiment according to FIG. 3, hejßpellets are more gently "Pretreatment enforced.

Figure 4 is a schematic vertical section through a double inclined furnace, which can be used with advantage at the place of the shaft furnace.

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An installation for executing the method according to the invention consists in essentially from the shaft furnace 1, the separation container 2, for the separation of Form coke and fine coke, e.g. by means of a bar grate 3, the pneumatic Conveyor line 4 for heating and circulation of the heat carrier serving fine coke, the bunker 5 for storing the hot heat carrier,

the cyclone 6 for dedusting the coking gas, the condensation coke Direction 7 for cleaning the coking gas and the foil cooler 8.

These parts of the system, which are common to all three embodiments, are shown in the Flow diagrams 1, 2 and 3 are denoted by the same reference numerals.

According to Figure 1, the non-baking, fine-grained coal, e.g. grain 0-3 mm, optionally after pre-drying in a system not shown in the scheme, fed into the coking shaft 1 from above. In the top of this The egg-shaped hot briquettes to be coked are also made with a shaft

Temperature of approx. 400 C as well as that from the separating bunker 5 continuously incoming fine coke heated to approx. 100O C. is introduced.

The hot briquettes have a unit weight of e.g. 30 g. They were made from a mixture of about 30% dry, dusty charcoal and approx. 70% fine-grained fine coke produced in the process according to the invention, which was briquetted e.g. at 430 C on a double roller press.

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The proportion of fine coal to hot briquettes is in the coking shaft between 0.3 and 2/0, preferably between 0.7 and 1.3 primarily according to the mixing ratio of coke to baked charcoal in the briquette. The quantity ratio of heat carrier to coking material moves between 3 and 10, preferably between 5 and 7. It mostly depends on

the selected process temperatures.

Suitable feeding devices ensure a good mixing of the three Material provided. As a result of the intense heat transfer from the highly heated Fine coke on the coking goods, the latter are degassed very quickly. The final temperature is usually chosen to be around 900 ° C. The coking, shaft 1 is dimensioned in its upper part so that the resulting distillation gases and vapors at a rate of e.g. B. 0.3 to 3.0 m / sec. flow upwards so that the fine-grained parts of the charge in swirling Movement can be displaced. Thereby the heat transfer and the Mixing of the introduced materials is supported. The mixture sinks slowly downwards in the shaft and equalize any remaining temperature differences the end. This compensation is favored by some cone, double cone or roof-shaped fixtures, which reduce the relative movement between fine coke by narrowing and widening the free shaft cross-section and briquette coke and, if necessary, to the drainage or supply

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of gases and / or vapors can serve /

The same effects can also be achieved if the shaft is used as a double inclined furnace forms according to Figure 4, in which the shaft in two on top of each other arranged halves is divided, in each of which a shaft wall is inclined. It follows that the free viewing cross-section over the height of the furnace steadily and a relative movement within the downward

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wandering bulk material "is forced.

At the lower end of the shaft, the coke is discharged at temperatures around 900 C. and gets into the separating container 2. Doi-t, e.g. by "slanting" Grate 3, briquette coke and fine coke separated from each other. The former is cooled in the coke cooler 8 by gases which are circulated via the air preheater 9 will. "Some of the fine coke is routed to riser 4, from there Combustion gases pneumatically conveyed into the bunker 5 and at the same time heated again to approx. 1000 C, on the other hand it is heated by w

the discharge 10 e.g. by a chute or a closed conveyor fed to the briquetting system. The heating gas for reheating the heat carrier, which also serves as a pneumatic conveying means in the riser 4, as a precautionary measure by burning the distillate gas produced in the process generated with the burner. II. But you can also use other gaseous or use liquid fuels. The combustion gases, which convey the coke pneumatically, can also be released by introducing preheated air

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and partial combustion of the circulating coke are formed when the the resulting slight increase in the coke ash content can be accepted.

The gaseous and vaporous coking products are at a temperature from approx. 900 C at the top of shaft 1, dedusted dry in cyclone 6 and cooled, partially condensed and cleaned in the condensation device 7 The Kosstaub separated in the cyclone 6 is together with the fine coke transported to the hot briquetting system. That in the separating bunker 5 from the coke Exempted, about 1000 C hot flue gas is either through a waste heat boiler or you can use your heat content in a drying system, for example in which the fine coal to be used is pre-dried.

The embodiment according to Figure 2 differs from that according to Fig. 1 only in that the coking of the baking fine coal does not take place together with the briquettes in the shaft 1, but in a separate one The bubble bed in the upper end of the shaft furnace above the briquette feed or, as shown in FIG. 2, in the additional chamber 12 can be arranged, under the action of the hot heat carrier, which from the Separation bunker 5 is running. The mixture of heat transfer medium and freshly formed fine coke runs out of chamber 12 at the bottom at a temperature of e.g. 950 ° C and serves as a heat carrier for the coking of the briquettes in shaft 1. At

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the production of the briquettes is used in the present case as a binding component Dust-like charcoal of the same type used as it is used in chamber 12 to produce the fine-grain coke, otherwise corresponds the method according to Fig. 2 is quite similar to that shown in Fig. 1.

With briquettes or pellets, the moisture and / or a lot of bitumen or contain other volatile constituents, the shock is very rapid Heating, which is advantageous in coking hot briquettes, harmful "

as long as de moldings do not have a minimum temperature of about 600 to 700 C. have exceeded. The embodiment according to FIG. 3 therefore uses the example of the coking of hot pellets as a gentle preheating of the pellets up to this minimum temperature ΰη a purge gas 13 before, in which as a heat carrier hot distillation gas from the coke cooler 8 is used. This gas will at the end of the condensation device 7 removed cold, via a fan 14 conveyed into the coke cooler 8 and heated there. The hot gas causes in the purging gas shaft 13 a gentle smoldering of the pellets. It leaves φ

the purge gas shaft in a mixture with the carbonization gases and tar vapors, which emerge from the pellets when they are heated, with temperatures around 400 C. and air condensation device 7 flows back again. The melted pellets and freshly supplied, possibly pre-dried fine coal are in the coking * Shaft 1 brought together with a heat transfer medium at a temperature of approx. 1000 ° C and coked very quickly in the process. The heat transfer medium for coking is, as in the other examples of self-produced fine coke and runs continuously from the

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Separation bunker 5 closed. The separation of the fine coke from the coked pellets takes place in the separating container 2, e.g. through an inclined bar grating 3. The Part of the fine coke is returned to the separator bunker 5 via the riser 4, the excess is fed to the pelletizing device in a hot state.

The method according to the invention is * e.g. also suitable for coking pellets, which are made from self-produced fine coke in a cold state with the addition of baking coal and / or other binders and water are. Such input material requires pre-drying and sometimes also partial degassing before it can be shock-like in the high-temperature stage May undergo heating. Accordingly, the process can be modified, for example by adding an additional drying step for which provides pellets. In this, for example, the exhaust gases from the separation bunker of the heat transfer circuit can be used as a heating and drying medium be used.

In the figure 4 a double inclined furnace is shown schematically in vertical section, which can be used instead of the shaft furnace 1 for coking moldings and fine coal by mixing with hot heat transfer medium.

The double inclined furnace consists of the upper furnace section 20 with the feed 21 for briquettes, fine coal and heat transfer media and with the discharge 22 for the distillation gas and the lower furnace section 23 with the discharge

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24 for the after degassing gas and the coke outlet 25 at the lower end, - both Oven sections each have a vertical wall 26, 27 and an inclined oven wall 28, 29 and are connected to one another via the narrowed passage 30.

The fine coal and the briquettes are mixed with hot in a suitable mixture Heat transfer medium introduced into the furnace from above through feed 21. At the top Oven section 20, through the volatile coking products derived at 22, the fine-grained components - the coating in a large cross section of the upper area set in a whirling motion. In the lower area of the upper section of the furnace, the development of gas quickly subsides, so that there forms a fixed bed which migrates down through the narrowed passage 30 and the lower furnace section. Due to the increasing narrowing of the Cross-section in "both furnace sections is a relative movement within the downward moving bulk brought about, whereby a rapid temperature equalization between the heat carrier on the one hand and the fine coal and the Form coke on the other hand brings about. In the older section of the stove it rises the bulk off, so that there is a special collecting space 31 for the volatile Forms products of post-degassing. The one removed through the opening 24 Gas is practically tar-free and rich in hydrogen and can optionally be used separately can be treated and used by the distillation gas of the upper section of the furnace.

Directly heated double chamber furnaces of this type are used for cold firing

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turns. Of the advantages they have for working with solid fine Offer heat carriers, has not yet been used. «

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Claims (1)

1.) Process for the production of shaped coke from fine-grain fuels, which are deformed by briquetting or pelletizing, in a shaft furnace by direct heating with fine-grain coke as a heat carrier, which are passed through / shaft furnace in cocurrent with the moldings, characterized in that fine-grained coal and the slugs in the same process we coke that it is made from the fine coal Fine coke formed is used as a heat carrier and is circulated through the shaft furnace and a heating zone, and that from A partial flow of the fine coke is branched off from the heat carrier circuit and used as a component for the production of the moldings will. 2.) The method according to claim 1, characterized in that niehtbackende Fine coal and the briquettes are coked together in the shaft furnace, 3.) The method according to claim 1, characterized in that baking coal is coked by mixing with the hot heat carrier, and that the resulting hot mixed coke is brought to act on the briquettes. 109837/03 U .'-_ Process according to claims 1 to 3, characterized in that the briquettes before being mixed with the heat carrier by means of hot • Purge gases are dried and / or gently smoldered. 5. y The method of claim 4, characterized in that the exhaust gas from the heating he'isse desWärmeträgers is used as purge gas. 6.) The method according to claim 4, characterized in that the flushing gas the degassing gas of the coking is used after reheating by direct heat exchange with the hot molded coke. 7.) The method according to claim 1, characterized in that the fine coal to be used is dried with hot gas from the coking process will. 8.) Process according to claims 1 to 7, characterized in that the gases from coking with a hot heat transfer medium and from the pretreatment of the bricks or fine coal through a joint condensation be guided. 9) device for carrying out the method according to claims 1 to S, characterized by a shaft furnace 1 with the downstream 10983 7/034 3 " ¹⁸ " Rod grate separator 3, dfe conveyor line for fine coke 4 and the fine coke separator 5. ■ 10.) Device according to claim 9, characterized by a purge gas Shaft-shaped pretreatment room 13. 11.) Device according to claim 9 / characterized by / the heat transfer circuit switched on pretreatment room 12. 12.) Voi'i'ichtung according to claim 9 _t, characterized in that the shaft furnace is a double inclined furnace. 1098 37/0 3 43